1. Field of the Invention
The invention relates to a USB plug with a built-in card-reading slot, and more particularly to an A-Type USB plug with a built-in card-reading slot. Moreover, the normal USB plug function is still fulfilled.
2. Description of the Related Art
Universal Serial Bus is referred to as USB. It has been developed and designed by many computer companies, such as Compaq, Intel, Microsoft, Digital Equipment, NEC, IBM and Nortel.
USB connector is a standard interface and unified the connectors of a variety of peripheral devices such that it is regarded as a “universal connector”. With the development of electronics, communications and digital technologies, USB connector plays an indispensable role in the computer field.
FIG. 1 shows a perspective view of a transmission cable connector of a conventional USB plug. According to the specification of an A-Type USB plug, the external thickness t1 of the metal housing 11 is 4.52 mm while the thickness of an isolation substrate 12 enclosed by the metal housing 11 is approximately 1.5˜2.0 mm such that the metal housing 11 internally creates a slot 13 in electric connection to a USB female plug (not shown). It is a pity that the conventional USB plug 10 only establishes an electric connection over a cable connector to another electronic product 80 and does not have other functions.
As new digital products continue to be introduced on the market, a variety of memory cards with different specifications and capacities has been developed, such as Micro SD and Mini SD that are a small and a large SD memory card, respectively. Since there are memory cards, card readers are needed and serve as an interface between the host computer and the memory card. The data transmission takes place by means of a USB jack in the host computer. However, most of the card readers on the current market have a large size. Compared with a small memory card, the card reader really occupies much space, thereby increasing much inconvenience in use.
As a result, a memory card reader 20, as shown in FIGS. 2A and 2B, is developed. A substrate 24 is received within a cavity 22 of a plug 21. A contact finger interface 25 is fitted to the front surface of the substrate 24 while conductive strips 26 are positioned at the rear surface thereof. In this way, a card-reading slot 23 (or a card reader) is formed at the tail thereof for the insertion of a memory card 27. The memory card 27 includes an access interface 28 that is electrically connected to the conductive strips 26. As a result, a smooth access of data is ensured when the plug 21 is connected to the computer. The memory card reader 20 has the advantages of light weight und thin structure. However, the card-reading slot 23 is disposed at the opposite side of the USB plug 21. Therefore, it can be used only as a card-reader, but it is not possible to fulfill other functions. This requires further improvements.